Gentlemen,
You're watching your juice-coated dick sliding in and out of her pussy, the engorged lips clasped around your shaft. Suddenly, she lifts her pussy from your cock and grabs it in her fingers. Your cock is coated with her excitement. You watch as her tongue slithers up your length before disappearing inside her mouth. You shudder as you watch her get a taste of her own juice as she pleasures you orally.
Ladies, what's the visual equivalent and turnon for you?